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Thomas GA, Paradell Gil T, Müller CT, Rogers HJ, Berger CN. From field to plate: How do bacterial enteric pathogens interact with ready-to-eat fruit and vegetables, causing disease outbreaks? Food Microbiol 2024; 117:104389. [PMID: 37919001 DOI: 10.1016/j.fm.2023.104389] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 09/11/2023] [Accepted: 09/17/2023] [Indexed: 11/04/2023]
Abstract
Ready-to-eat fruit and vegetables are a convenient source of nutrients and fibre for consumers, and are generally safe to eat, but are vulnerable to contamination with human enteric bacterial pathogens. Over the last decade, Salmonella spp., pathogenic Escherichia coli, and Listeria monocytogenes have been linked to most of the bacterial outbreaks of foodborne illness associated with fresh produce. The origins of these outbreaks have been traced to multiple sources of contamination from pre-harvest (soil, seeds, irrigation water, domestic and wild animal faecal matter) or post-harvest operations (storage, preparation and packaging). These pathogens have developed multiple processes for successful attachment, survival and colonization conferring them the ability to adapt to multiple environments. However, these processes differ across bacterial strains from the same species, and across different plant species or cultivars. In a competitive environment, additional risk factors are the plant microbiome phyllosphere and the plant responses; both factors directly modulate the survival of the pathogens on the leaf's surface. Understanding the mechanisms involved in bacterial attachment to, colonization of, and proliferation, on fresh produce and the role of the plant in resisting bacterial contamination is therefore crucial to reducing future outbreaks.
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Affiliation(s)
- Gareth A Thomas
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Teresa Paradell Gil
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Carsten T Müller
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Hilary J Rogers
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Cedric N Berger
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK.
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2
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Vassallo A, Amoriello R, Guri P, Casbarra L, Ramazzotti M, Zaccaroni M, Ballerini C, Cavalieri D, Marvasi M. Adaptation of Commensal Escherichia coli in Tomato Fruits: Motility, Stress, Virulence. BIOLOGY 2023; 12:biology12040633. [PMID: 37106833 PMCID: PMC10136321 DOI: 10.3390/biology12040633] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/07/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023]
Abstract
Food contamination can be a serious concern for public health because it can be related to the severe spreading of pathogens. This is a main issue, especially in the case of fresh fruits and vegetables; indeed, they have often been associated with gastrointestinal outbreak events, due to contamination with pathogenic bacteria. However, little is known about the physiological adaptation and bacterial response to stresses encountered in the host plant. Thus, this work aimed to investigate the adaptation of a commensal E. coli strain while growing in tomato pericarp. Pre-adapted and non-adapted cells were compared and used to contaminate tomatoes, demonstrating that pre-adaptation boosted cell proliferation. DNA extracted from pre-adapted and non-adapted cells was sequenced, and their methylation profiles were compared. Hence, genes involved in cell adhesion and resistance against toxic compounds were identified as genes involved in adaptation, and their expression was compared in these two experimental conditions. Finally, pre-adapted and non-adapted E. coli were tested for their ability to resist the presence of toxic compounds, demonstrating that adaptation exerted a protective effect. In conclusion, this work provides new information about the physiological adaptation of bacteria colonizing the tomato fruit pericarp.
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Affiliation(s)
- Alberto Vassallo
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Roberta Amoriello
- Department of Biomedical, Experimental and Clinical Sciences, University of Florence, 50134 Florence, Italy
| | - Prandvera Guri
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Lorenzo Casbarra
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Matteo Ramazzotti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134 Florence, Italy
| | - Marco Zaccaroni
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Clara Ballerini
- Department of Biomedical, Experimental and Clinical Sciences, University of Florence, 50134 Florence, Italy
| | - Duccio Cavalieri
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
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Dolores Arista-Regalado A, Barba-León J, Humberto Bustamante V, Alberto Flores-Valdez M, Gaona J, Juliana Fajardo-Guerrero M. hilD is required for the active internalization of Salmonella Newport into cherry tomatoes. J Food Prot 2023; 86:100085. [PMID: 37003533 DOI: 10.1016/j.jfp.2023.100085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 04/03/2023]
Abstract
Salmonella enterica is a foodborne pathogen that can be internalized into fresh produce. Most of the Salmonella virulence genes are clustered in regions denominated Salmonella Pathogenicity Islands (SPI). SPI-1 encodes a Type Three Secretion System (T3SS-1) and effector proteins that allow the internalization of Salmonella into animal cells. HilD is a transcriptional regulator that induces expression of SPI-1 genes and other related virulence genes located outside of this island. Here, we assessed the role of hilD in the internalization of Salmonella Newport and Typhimurium into cherry tomatoes, by evaluating either an isolate from an avocado orchard, S. Newport-45, and the laboratory strain S. Typhimurium SL1344 and their isogenic mutants in hilD. The internalization of these bacteria was carried out by using a temperature gradient of 12 °C. The transcription of hilD and invA was tested by qRT-PCR experiments. Our results show that S. Newport-45 hilD mutant viable cells obtained from the interior of the fruit were decreased (2.7-fold), compared with those observed for S. Typhimurium SL1344. Interestingly, at 3 days post-inoculation, the cells recovered from S. Newport-45 hilD mutant were similar to those recovered from all the strains evaluated, suggesting that hilD is required only for the initial internalization of S. Newport.
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Li WJ, Li HZ, An XL, Lin CS, Li LJ, Zhu YG. Effects of manure fertilization on human pathogens in endosphere of three vegetable plants. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 314:120344. [PMID: 36206891 DOI: 10.1016/j.envpol.2022.120344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
Pathogens can colonize plant endosphere and, be transferred into human beings through the food chain. However, our understanding of the influences of agricultural activities, such as fertilization, on endophytic microbial communities and human pathogens is still limited. Here, we conducted a microcosm experiment using the combination of 16 S rRNA gene amplicon sequencing and high-throughput qPCR array to reveal the effects of manure fertilization on microbiomes of soils and plants and how such impact is translated into endophytic pathogens. Our results showed that manure fertilization significantly altered soil microbiomes, whereas with less influence on endophytic microbial communities. Soil is a vital source of both bacterial communities and human pathogens for the plant endosphere. The abundance of pathogens was increased both in soils and endosphere under manure fertilization. These findings provide an integrated understanding of the impact of manure fertilization on endophytic pathogens.
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Affiliation(s)
- Wen-Jing Li
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China
| | - Hong-Zhe Li
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China
| | - Xin-Li An
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China
| | - Chen-Shuo Lin
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China
| | - Li-Juan Li
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China
| | - Yong-Guan Zhu
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China; State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
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Lenzi A, Baldi A, Lombardelli L, Truschi S, Marvasi M, Bruschi P. Contamination of microalgae by Salmonella enterica and Escherichia coli is influenced by selection breeding in chicory ( Cichorium intybus L.). FOOD QUALITY AND SAFETY 2022. [DOI: 10.1093/fqsafe/fyac030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Objectives
The aim of this study was to assess whether selection breeding in chicory (Cichorium intybus L.) led changes in the susceptibility to Salmonella enterica and Escherichia coli contamination and whether the anatomical traits of the leaves are involved in the possible changes.
Materials and Methods
Five chicory genotypes subjected to different intensities of selection were compared at the microgreen stage. Bacterial retention was evaluated after leaf incubation for 1.5 h on the surface of the bacterial suspension, followed by rinsing, grinding, plating on selective media, and CFU counting. The density of stomata and trichomes, total stomatal length and width, stomatal pit width, surface roughness and sharpness were evaluated.
Results
The intensively selected genotype (Witloof) was significantly more prone to contamination ((2.9±0.3) lg CFU/cm 2) as the average of the two bacteril types than the wild accession (Wild) ((2.3±0.4) lg CFU/cm 2) and the moderately selected genotypes (two leaf chicories, Catalogna type, and root chicory ‘Magdeburg’) (on average, (1.9±0.3) lg CFU/cm 2). Witloof microgreens also showed larger stomata (on average + 34% for stoma width and + 44% for pit width), which could justify, at least in part, the higher susceptibility to enterobacteria contamination. In fact, when contamination was performed in the dark (closed stomata), the bacterial retention in Witloof was significantly reduced in comparison with the opened stomata (-44%) and in Wild (-26%). Differences in retention between Witloof and Wild were still observed after UV treatment. The hierarchical clustering performed by grouping the leaf anatomical features was consistent with the chicory genetic groups.
Conclusions
Our results suggest that the domestication process can affect the safety of produce and that the micromorphological traits of the leaves may be involved.
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Affiliation(s)
- Anna Lenzi
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Florence, Italy
| | - Ada Baldi
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Florence, Italy
| | - Letizia Lombardelli
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Florence, Italy
| | - Stefania Truschi
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Florence, Italy
| | | | - Piero Bruschi
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Florence, Italy
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Doren J, Hadad R, McKEAG L, Tucker C, Newbold E. Food Safety Risks of Harvesting Dropped and Drooping Produce: A Review. J Food Prot 2022; 85:571-582. [PMID: 34914837 DOI: 10.4315/jfp-21-369] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/10/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT The Produce Safety Rule of the Food Safety Modernization Act (FSMA) sets forth minimum standards for fruit and vegetable production in the United States. One provision states that growers must not harvest dropped produce because damage or ground contact may contaminate produce. In an unpublished survey of 2020 food safety inspections conducted by the Northeast Center to Advance Food Safety, handling of dropped produce covered by the FSMA was a common misunderstood and noncompliance issue among growers in the Northeast. In consideration of this provision's on-farm practicality, this review was conducted to evaluate the risks associated with dropped and drooping produce, to guide growers in making informed risk management decisions, and to answer the following questions: (i) what are the risk factors that influence transferability of pathogens from touching the ground to produce and (ii) what are the risks associated with harvesting dropped or drooping produce covered under the Produce Safety Rule? A search of online databases revealed 12 relevant publications, which highlighted moisture, contact time, and crop features as affecting contamination rates from a ground surface to a crop surface. Soil and mulch posed a differential risk, with bare soil generally presenting a lower risk than plastic mulch. The effects of other mulch types are unclear. Mulches may promote pathogen persistence in soil, although they may also protect produce from contaminated soils. These studies were limited in their scope and applicability and most did not directly address dropped produce. Research is needed to clarify the various effects of dropped and drooping produce, the impact of ground surface type on pathogen survivability and transfer, soil and crop features that facilitate contamination, and postharvest risks of harvesting dropped or drooping produce. A comprehensive understanding of these issues will guide growers in implementing preventive measures and better managing risk in a way practicable to each farm's unique conditions. HIGHLIGHTS
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Affiliation(s)
- Johanna Doren
- Northeast Center to Advance Food Safety, University of Vermont Extension, Bennington, Vermont 05201
| | - Robert Hadad
- Cornell Vegetable Program, Cornell Cooperative Extension, Rochester, New York 14617
| | - Lisa McKEAG
- Center for Agriculture, Food, and the Environment, University of Massachusetts Extension, Amherst, Massachusetts 01003, USA
| | - Caitlin Tucker
- Cornell Vegetable Program, Cornell Cooperative Extension, Rochester, New York 14617
| | - Elizabeth Newbold
- Northeast Center to Advance Food Safety, University of Vermont Extension, Bennington, Vermont 05201
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Expiration Date of Ready-to-Eat Salads: Effects on Microbial Load and Biochemical Attributes. Foods 2021; 10:foods10050941. [PMID: 33923060 PMCID: PMC8145991 DOI: 10.3390/foods10050941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/14/2021] [Accepted: 04/23/2021] [Indexed: 11/16/2022] Open
Abstract
When minimally processed vegetables reach their expiration date, expose an increased microbial load. This includes mainly spoilage microorganisms but also foodborne pathogens, thus affecting the quality and safety of highly consumed ready-to-eat salads. A total of 144 ready-to-eat salads from the Cypriot market were analyzed in an attempt to determine the effects of the expiration date on the microbial load and plant metabolic variables of the salads. Possible correlations between them were also investigated for the first time. Furthermore, the impacts of the season (winter, summer), salad producing companies and type of salad and/or their interactions with the tested parameters were investigated. Results revealed that the microbial load (mainly spoilage microorganisms, such as Pseudomonas spp., yeasts and molds) increased towards the end of the shelf life. The microbial load was differentiated among the five salad producers and/or the salad types, highlighting the importance of a common and safe sanitation-processing chain in the preparation of ready-to-eat salads. Summer was the season in which Escherichia coli counts were found to be higher for plain lettuce, while Staphylococcus spp. was increased numbers for the lettuce+endive/radicchio, lettuce+rocket and lettuce+chives type of salads. Additionally, an increased Staphylococcus spp. was observed for plain rocket salads in winter. All samples examined were found negative for Salmonella enterica and Listeria monocytogenes. Moreover, carbon dioxide production and damage indexes (hydrogen peroxide and lipid peroxidation) increased on expiration date on both winter and summer seasons, indicating plant tissue stress at the end of shelf life. These findings indicate that the expiration date and relevant shelf life of processed vegetables are important parameters to be considered when postharvest management is applied to these products, ensuring safety and quality.
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Lenzi A, Marvasi M, Baldi A. Agronomic practices to limit pre- and post-harvest contamination and proliferation of human pathogenic Enterobacteriaceae in vegetable produce. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107486] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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